The present invention relates to a locking mechanism for protection of the hydraulic circuit, called hydra lock, for preferably mechanically driven vehicles, including vessels/boats, in which in mentioned hydraulic circuit for example the steering gear and/or braking system can be admitted in order to prevent the illegal use of mentioned mechanically driven vehicles, in which the mentioned locking mechanism for protection of the hydraulic circuit can contain a valve of a special construction with a housing provided with inlet and outlet ports for hydraulic fluid and a drivable inner core instrument in the form of a movable cylinder inside the mentioned housing also provided with bores, which can correspond with mentioned inlet and outlet ports in order to form the required passage.
A similar safety device or system is known in the American patent title: xe2x80x9cAnti-Theft System for Vehiclesxe2x80x9d by Yehuda Baruch from Israel, number 4,765,362, dated Aug. 23, 1988.
It concerns a locking mechanism or system for installation mostly in Trucks to prevent illegal use of them. It concerns a construction of a 3/2-valve for placement in the hydraulic circuit of the concerned truck. The mentioned 3/2-valve has a special construction, in which in a tubular housing and inlet and outlet valve are applied, which can correspond with bores in the movable solid core cylinder inside the housing for either or not passing of the hydraulic fluid. The system works on the steering system on one hand and on the braking circuit on the other hand. The control of the movable solid cylinder takes place directly by means of a key and lock construction at the upper side of it, in which by means of spring loaded balls in the bores of the movable solid core cylinder, ports and bores are sealable and the position of the core cylinder is stabilized.
The safety is based on sealing the return circuit of the hydraulic system by means of a 3/2-valve, which can be turned mechanically in two positions with a key. The existing return mains of the steering gear housing (or brake housing) is interrupted and between this the valve is mounted which is normally in the opened position. Also, the pump pressure pipe is connected on the third port. The ignition key is applied on the dashboard, by which the valve part is situated in the motor compartment.
When sealing the hydraulic system a by-pass of the pump pressure to the (bleeded) oil-storage tank is created at the same time. So, the steering gear and/or braking system does not receive any supply pressure anymore and simultaneously the outgoing pipes are blocked. The pump cannot supply pressure anymore because the oil can flow freely into the bleeded oil-storage tank.
The known locking mechanism or system has the following disadvantages, namely that professional educated thieves can quite quickly break into or crack the system by means of manipulation of the lock construction with key means. Furthermore is an extra key an extra element for the truck driver that he has to treat carefully and that could easily be stolen on resting areas, through which stealing the truck becomes rather easy. Further the hydraulic circuit around the locking mechanism can be short-circuited with extra wires. From the above follows that the known locking mechanism has several disadvantages concerning safety, such as:
the system can be influenced manually with a key, also during driving;
the mechanical system is not combined with advanced modem electronics; and
during driving thee is not absolute guarantee that the valve cannot block spontaneously.
The increasingly ongoing safety laws and demands from insurance companies caused the need for advanced and absolutely safe equipment. The system must not be controlled by human intervention and may absolutely not be able to block spontaneously during driving.
The aim of the present invention is to provide in a locking mechanism as such, which eliminates the above described disadvantages.
For this purpose a locking mechanism is developed as such in a very inventive way, that the mentioned locking mechanism is composed of a cylindrical tubular housing provided with two inlet ports one outlet port, a special inlet port with a locking or securing cylinder for operation of a safety pin, in which in mentioned cylindrical tubular housing a movable solid core cylinder with bores is applied, so that roughly the working of a 3/2-valve arises, in which the mentioned solid core cylinder by means of an electromotor with reduction gearbox can be mechanically driven, in which the drive of the mentioned electromotor takes place by an electronic circuit, in which also an encoder unit with starter, a sensor for the lock of the bonnet and a sensor for the oil pressure and such are included, in which the mentioned locking mechanism together with the mentioned electronic circuit is mounted in a closed steel housing, which is build in under the bonnet preferably on a difficult reachable place, which locking mechanism is applied in mentioned hydraulic circuit of the mechanically driven vehicle, also called automobile and often truck, or it can also be a vessel in which the in the hydraulic circuit the built in locking mechanism is diagrammatically indicated and of which the working is shown in FIGS. 1, 4, 6 and 8 in the so called blocked position and in FIGS. 2, 5, 7 and 9 in the so called driving or deblocked position, and by which the mentioned locking cylinder for operating the safety pin is indicated in FIGS. 5, 7 and 9, by which the locking of the mentioned solid core cylinder for reasons of safety is indicated with bores in the driving or release or deblocked position and in FIGS. 4, 6 and 8, as indicated because of the fall out of the pressure of the hydraulic fluid, is there no more locking of the mentioned core cylinder.
The advantages and details of the locking mechanism according to the present invention mentioned in claim 1 are described below. The rotatable valve is maintained but the control is now done by means of a small electromotor with reduction gear unit. The complete unit, including the electronics, is mounted in a steel demolition-proof construction. In order to be able to start the motor, one must, while starting the vehicle, enter a unique electromagnetic code on the dashboard. This last system is unique in combination with the hydraulic locking mechanism. Further there is an automatic mechanical safety device against the rotation of the valve during driving, currently a requirement in relation to safety. This lock is achieved by a special, hydraulic spring return cylinder (locking cylinder) that is operated by the oil or hydraulic fluid and that is fixedly mounted on the valve body. After stopping the motor of the vehicle the oil pressure falls after some time (about 30 seconds), the locking or securing cylinder pulls itself out of the piston by its own spring force and thus the displacement of the core cylinder to the anti-theft position shall be made possible again. Conversely the safety pin of the locking or safety cylinder can protrude again (=locking during driving) as soon as the oil pressure on the mentioned cylinder occurs. This oil pressure arises when the motor of the vehicle is started according the secured electronic procedure, the pump then starts building up pressure on the hydraulic system o the leads and the valve motor seals the free by-pass to the oil reservoir (at the same time the sealing of the return oil of the steering gear is released). If during this procedure the safety pin of the locking cylinder knocks against the core cylinder too soon and consequently cannot yet fall into the lock, it will not be a problem. The core cylinder is made of steel and is for running in with the reduction gear unit and such. When the core cylinder is brought into the correct position by the motor the safety pin will still fall into the lock.
Following the locking mechanism according to the invention in a first variant is further developed wherein the mentioned core cylinder can be moved in an up- and down going movement by means of a spindle construction driven by mentioned electromotor with reduction gearbox, as indicated in FIGS. 6 and 7 and by which the electronic system is switched by means of a protruding shaft with collar.
The advantage of this is a solid and very safe lockable solution. The movement is realized by a spindle, which is driven by an electromotor. In order to lock the piston against rotating a locking pin is screwed in the housing. The locking pin can, in a longitudinal groove make the correct movement of the piston possible. Here, two switches can also detect the actual position.
Then the locking mechanism according to the invention in a second variant is further developed in such a way that the mentioned core cylinder is rotatable by means of the shaft of the electromotor with reduction gearbox over a fixed angle of for example 90xc2x0, in which a protruding quarter part of the shaft, which is connected with the mentioned core cylinder, operate the switches of the electronic system.
The advantage of this is also a solid and very safe lockable locking mechanism. The piston position is limited in the utmost positions by two cams that make a maximum rotation in a fixed angle possible of for example 90xc2x0. Also, on these cams two limit switches are mounted, which are connected with the electronic circuit. If the piston would rotate without permission, the piston valve motor will start the rotation again till the end position and stops.
Further the locking mechanism according the invention is further developed in such a way, that the construction of the mentioned electromotor and electronics is such that these can work on a battery voltage of approximately 8 Volt.
The advantage is that the electromotor and the electronics already work at a battery voltage of 8 Volt (usually 12 Volt). While stopping with a half charged battery one can thus still switch to the anti-theft position.